Setting up Qt Creator for Pi Pico RP2040 development

Qt Creator is tricky to set up for RP2040/Pi Pico development, but fairly quick once you know the steps. I was unable to make Pico projects run correctly under VS Code using Raspberry's suggested editor extension.

Note: These are personal notes from setting up Qt Creator for Raspberry Pi Pico 1 development on a new machine, organized into an article after the fact. They are specific to my machine (Arch Linux, fish shell) and may have missing or outdated steps, which may not fully succeed on a new machine or user account.